Background: We aimed to characterise the geographical distribution of Sørensen-based multi-site dissimilarity (β_sor) and its underlying true turnover (β_sim) and nestedness (β_sne) components for Chinese Lauraceae and to analyse their relationships to current climate and past climate change.
Methods: We used ensembles of small models (ESMs) to map the current distributions of 353 Lauraceae species in China and calculated β_sor and its β_sim and β_sne components. We tested the relationship between β_sor, β_sne and β_sim with current climate and past climate change related predictors using a series of simultaneous autoregressive (SAR_err) models.
Results: Spatial distribution of β_sor of Lauraceae is positively correlated with latitude, showing an inverse relationship to the latitudinal α-diversity (species richness) gradient. High β_sor occurs at the boundaries of the warm temperate and subtropical zones and at the Qinghai-Tibet Plateau due to high β_sne. The optimized SAR_err model explains β_sor and β_sne well, but not β_sim. Current mean annual temperature determines β_sor and β_sne of Lauraceae more than anomalies and velocities of temperature or precipitation since the Last Glacial Maximum.
Conclusions: Current low temperatures and high climatic heterogeneity are the main factors explaining the high multi-site β-diversity of Lauraceae. In contrast to analyses of the β-diversity of entire species assemblages, studies of single plant families can provide complementary insights into the drivers of β-diversity of evolutionarily more narrowly defined entities.